The given question is incomplete. The complete question is as follows.
In a nuclear physics experiment, a proton (mass 
kg, charge +e = 
C) is fired directly at a target nucleus of unknown charge. (You can treat both objects as point charges, and assume that the nucleus remains at rest.) When it is far from its target, the proton has speed 
m/s. The proton comes momentarily to rest at a distance 
m from the center of the target nucleus, then flies back in the direction from which it came. What is the electric potential energy of the proton and nucleus when they are 
m apart?
Explanation:
The given data is as follows.
Mass of proton = 
kg
Charge of proton = 
Speed of proton = 
Distance traveled = 
We will calculate the electric potential energy of the proton and the nucleus by conservation of energy as follows.
= 
where, 
U = 
Putting the given values into the above formula as follows.
U =
= 
= 
Therefore, we can conclude that the electric potential energy of the proton and nucleus is .
Answer:
The gravitational force is related to the mass of each object.
The gravitational force is an attractive force.
Explanation:
Gravitational force is a long range force of attraction between any two masses.
Mathematically given as :
where:
are the masses
r= distance between the center of mass of the two objects.
G= gravitational constant = 
From the above relation of eq. (1) it is clear that,
Gravitational force is inversely proportional to the square of the distance and directly proportional to the masses.
The mass of an object is independent of its size due to the fact that density may vary for different objects.
The force of gravity varies with height as:
where:
gravity at height 
of the center of mass of the object from the center of mass of the earth.
and we know that force:
where: m= mass of the object.
Answer:
answer is C. 10 g
Explanation:
: When an object floats, it displaces an amount of water that has the same mass as itself. Therefore, the mass of the water in the graduated cylinder is equal to the mass of the object. We can see that there are 10 mL of water in the graduated cylinder. We also know that the density of water is 1 g/mL. Since each mL of water has a mass of 1 g, then 10 mL of water has a mass of 10 g. If the mass of the displaced water is 10 g, then the mass of the floating object is also 10 g.
The first person to say the Earth orbited the sun was Nicolaus Copernicus
